1. Field of the Invention
The present invention is broadly concerned with methods for scavenging and removal of arsenic and arsenic compounds from hydrocarbons in order to reduce substantially reduce the arsenic content of the hydrocarbons below commercially acceptable levels. More particularly, the invention is concerned with such methods making use of an effective amount of a composition comprising a triazine and a glycol ether, wherein the compositions are contacted with dewatered liquid hydrocarbon (e.g., crude or condensate oil containing no more than about 5% by volume water), preferably with agitation and subsequent settling, followed by separation of the treated hydrocarbon and a minor arsenic-rich aqueous fraction.
2. Description of the Prior Art
Oils and other hydrocarbons can contain significant quantities of arsenic, typically in the form of various arsenic compounds. Arsenic in this form is highly toxic and stringent government regulations prohibit the sale of oils containing high quantities of arsenic. Furthermore, it is known that the presence of arsenic in gasolines can cause permanent deactivation of catalysts in automotive pollution abatement catalytic converters. Accordingly, there exists a need to rapidly and economically scavenge arsenic from hydrocarbons containing unacceptably high quantities of arsenic.
A number of techniques have been proposed in the past to reduce the arsenic content of hydrocarbons. U.S. Pat. No. 3,782,076 describes a process for reducing the arsenic content of gaseous hydrocarbons by contacting the gas with a sorbent comprising a lead oxide. However, this technique is not suitable for liquid hydrocarbons.
U.S. Pat. No. 3,542,669 describes the removal of arsenic and arsenic derivatives from petroleum feedstreams by contacting the feedstreams with a lignite-based activated carbon. U.S. Pat. No. 4,849,577 teaches that arsenic and carbon oxysulfides may be removed from hydrocarbon cuts by liquid phase contact between the cuts and lead oxide. U.S. Pat. No. 5,169,516 advocates serial catalytic oxidation of hydrocarbon streams using a Cu/Zn/Al2O3 catalyst. However, these proposals involve rather complicated and expensive equipment, and are not suited for on-site or oil field treatment of arsenic-laden liquid hydrocarbons.